Abstract: The pH of a wound is assessed using a hydrogel film which changes colour in dependence upon pH. Suitably, the hydrogel film incorporates an indicator, across substantially its entire extent so that the film may be used to monitor pH across a wound. Wound pH information may be used to facilitate selection of the appropriate treatment to which the wound should be subjected. Suitably, the hydrogel film is incorporated into a dressing.

Abstract: Water problems in the production of oil or gas from subterranean formations is addressed by providing a method of restricting passage of a fluid from a first location to a second location in a subterranean formation by injecting into the formation a formulation comprising a first material, for example a dialdehyde, arranged to cross-link a second polymeric material, for example a polyvinyl alcohol, thereby to form a polymeric material of high viscosity which may block the passage between the first and second locations.

Abstract: A process for recovering materials from a subterranean formation, for example in enhanced oil recovery, comprises: (A) (a) (i) selecting a first polymeric material having a repeat unit of formula (A) wherein A and B are the same or different, are selected from optionally-substituted aromatic and heteroaromatic groups and at least one comprises a relatively polar atom or group and R1 and R2 independently comprise relatively non-polar atoms or groups; or (ii) selecting a first polymeric material prepared or preparable by providing a compound of general formula (B) wherein A, B, R1 and R2 are as described above, in an aqueous solvent and causing the groups C?C in said compound to react with one another to form said first polymeric material; (b) selecting a second polymeric material which includes a functional group which is able to react in the presence of said first polymeric material to form a third polymeric material; (c) causing the formation of said third polymeric material by a reaction involving said fir